How does CSS specificity decide which styles to apply?

Question

How does CSS determine when to apply one style over another?

I have been through the W3 CSS3 selectors document a few times, and that has helped me understand how to

Answer 1

http://www.w3.org/TR/CSS21/cascade.html#specificity is the official specificity specification.

But if that's TL;DR, the (too) short version is the more words you have in your selector, the higher the specificity. And with !important even higher. That's about it.

Edit: oh, I see that your link has the same information as mine. Sorry about that.